OpenModelica Encryption — OpenModelica User's Guide v1.28.0-dev-415-g3295ecd7e7 documentation

# OpenModelica Encryption

The encryption module allows the library developers to encrypt their libraries for different platforms. Note that you need a special version of OpenModelica with encryption support to do that, which is only released in binary form. This version contains an OpenModelica-specific private key that is used internally to decrypt the encrypted libraries for code generation only, not for display purposes.

If you are a library developer and are interested in distributing your library in encrypted form for use with OpenModelica, please contact us for further information. Please note that distributing the special version of OpenModelica with encryption support to the users of your library requires you to be a Level 2 member of the Open Source Modelica Consortium.

If you are a user of an encrypted library that is supported by OpenModelica, please contact your library supplier for information on how to get the special version of OpenModelica that runs it.

## Encrypting the Library

In order to encrypt the Modelica package call buildEncryptedPackage(TopLevelPackageName) from mos script or from OMEdit right click the package in Libraries Browser and select Export Encrypted Package or select Export > Export Encrypted Package from the menu.

All the Modelica files are encrypted and the whole library is zipped into a single file i.e., PackageName.mol. Note that you can only encrypt Modelica packages saved in a folder structure. The complete folder structure remains as it is. No encryption is done on the resource files.

## Loading an Encrypted Library

To load the encrypted package call loadEncryptedPackage(EncryptedPackage.mol) from the mos script or from OMEdit File > Load Encrypted Package.

## Notes

- Encryption support in OpenModelica does not include any license management, i.e., restricting the usage of a certain libraries based on some conditions, e.g., having paid a fee. It is only meant to prevent end users from seeing the Modelica source code of the encrypted parts of the libraries, for reasons of confidentiality or IP protection.

- The parts of the library that are protected by encryption are specified by the access control annotations defined by the Modelica Language Specification, Section 18.9.

- The generated C code corresponding to the encrypted parts of the library is obfuscated: all comments are removed, and all component names are replaced by generic names such as n1, n2, n3, etc. This prevents easy reverse-engineering of the encrypted library starting from generated simulation code.

- Encryption in OpenModelica is based on the SEMLA (Standardized Encryption of Modelica Libraries and Artifacts) module from Modelon AB, which provides a tool-independent framework for Modelica library encryption.